1. Technical Field
The present invention relates to a device mounting structure, device mounting method, electronic apparatus, liquid droplet ejection head, and liquid droplet ejection apparatus.
2. Related Art
As a method for disposing and electrically connecting a drive device such as an IC chip on a circuit board, the wire bonding method has been known for some time now. For example, even with respect to liquid droplet ejection heads (ink jet recording heads) used in the case of application of the liquid droplet ejection method (ink jet method) when forming images and manufacturing micro devices, a wire bonding method is used to connect piezoelectric elements for conducting ink ejection operations and a drive circuit (IC chip or the like) for supplying electrical signals to the piezoelectric elements (for example, see Japanese Unexamined Patent Application, First Publication No. 2003-159800 and Japanese Unexamined Patent Application, First Publication No. 2004-284176).
In conjunction with the ever higher integration of IC chips and the like in recent years, there has been a tendency for the external connection terminal of the IC chip and the like to become ever narrower, and to be given an increasingly narrow pitch. In this regard, there has also been a tendency to give an increasingly narrow pitch to the wiring patterns formed on the base substrate. Consequently, application of a connection method using the aforementioned wire bonding has become increasingly difficult.
Moreover, with respect to methods conducting image formation and micro device manufacture based on the liquid droplet ejection method, in order to realize increasingly minute detailing of the image or miniaturization of the micro device, it is preferable to make the distance between the nozzle apertures provided in the liquid droplet ejection head (the nozzle pitch) as small (narrow) as possible. As piezoelectric elements are multiply formed corresponding to the nozzle apertures, if the nozzle pitch is made small, the distance between the piezoelectric elements must also be made small, corresponding to the nozzle pitch. If the distance between the piezoelectric elements is made small in this manner, connection of the plurality of respective piezoelectric elements and the driver IC by the wire bonding method is difficult.
Furthermore, in conjunction with the increasingly compact size of electronic apparatuses, there is a growing need to electrically connect the device and the wiring of the base substrate via a step difference of the IC chip or the like in the device, or a step difference derived from the formation of the base substrate.